摘要: |
复合材料补片胶接技术是一种有效修复飞机受损铝合金构件的低成本方法。补片与铝合金材料热膨胀系数的显著差异,会在构件中引入残余热应力,对构件性能造成不利影响。文中采用单向碳/环氧复合材料补片对航空铝合金LY12CZ薄板进行单面补强,并通过确定应力释放温度测量了铝板及补片上的残余热应变。结果表明,对完好铝板而言,铝板和补片的残余热应变可分别达到-488 με和285 με;对于含中心裂纹铝板而言,裂纹长度对于残余热应变的影响较小。采用经典层合板理论和双金属片模型分别预测了复合材料补片及铝合金板在胶接面上的残余热应力。经典层合板理论对补片和完好铝板残余热应力的预测值分别为-79.8 MPa和50.8 MPa;双金属片模型的计算值偏大,分别为-98.4 MPa和64.6 MPa。 |
关键词: 残余热应力/应变 复合材料补片 铝合金 胶接修复 层合板理论 双金属片模型 |
DOI: |
分类号: |
基金项目:武器装备预研基金项目(编号略) |
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Thermal Residual Stresses in Bonded Composite Repair of Aluminum Substrates |
WANG Zun, ZENG Jing-cheng, XIAO Jia-yu, JIANG Da-zhi, YANG Fu-biao, WEN Si-wei
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College of Aerospace and Material Engineering, National University of Defense Technology, Changsha, Hunan 410073
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Abstract: |
Bonded repair technology has been proven an efficient and cost-effective means of repairing cracks, especially in aircraft aluminum structures. The significant difference in coefficients of thermal expansion between the composite patch and the aluminum will introduce thermal residual stresses in the structures, which may cause adverse effects on the mechanical properties. Unidirectional carbon/epoxy patches were used to repair the aerospace aluminum thin plates, LY12CZ, using single-sided patching technology. The stress free temperature was determined to measure the thermal residual strains in the patch and the substrate. The results show that the thermal residual strains in the aluminum and the patch are -488με and 285με, respectively, for the perfect aluminum substrate, and that crack length has slight effects on the thermal residual strains for the cracked aluminum substrate. Classical lamination theory and bimetallic strip model were used to predict the thermal residual stresses in the bonded surfaces. The thermal residual stresses in the patch and the aluminum, calculated by classical lamination theory, are -79.8 MPa and 50.8 MPa, respectively. Larger stresses are predicted by bimetallic strip model to be -98.4 MPa and 64.6 MPa, respectively. |
Key words: thermal residual stress/strain composite patch aluminum adhesively bonded repair lamination theory bimetallic strip model |